Impact-wheel or turbine.



Nu. s4|,847. Patented 1an. 23, |900. S. C. AVIDSN.V

IMPACT WHEEL 0R TURBINE.

(Application led Muy 8, i899.) (No Model.; 3 Sheets-Sheet l.

mi: Norms PETERS co, PHocLlTnn., wAsmNsmN. D. cA

No. 64I,847. Patented lan. 23, |900. S. C. DAVIDSON.

IMPACT WHEEL 0R TUBBINE.

(Application led May B, 1899.)

3 Sheets-Sheet 2.

(No Model.)

No. 641,347. Patented 1an. 23,1900. f s. c. nAvmsoN.

mPAcr wam on Tunsme.

(Applicatiun le'd May 8, 189B.)

3 Sheets-Sheet 3.

(No Model.)

UNITED STATES PATENT EFrcE.

IMPACT-WHEEL oR TURBINE.

SPECIFICATION forming part of Letters Patent No. 641,847, dated January23, 1900.

Application led May 8, 1899,` Serial NO; 7151934' (N0 mflel.)

' VIDsoN, merchant, of Belfast, Ireland,'have invented certain new anduseful Improvements in Impact-Wheels or Turbines, of which the followingis a specification.

My improvements relate to impact-wheels or turbines, and moreparticularly to the class or type known as Pelton wheels; and theobjects, among others, of my invention are to so construct the bucketsand the periphery of the wheel that together they shall combinesimplicity and lightness of construction with sufficient strength toresist the centrifugal force developed by the excessively highvelocities at which turbines of this class revolve when steam or waterat very high pressures is employed therewith as the motive fluid withoutthe said buckets being distorted or twisted thereby, and at the sametime toso arrange and combine the interior curvatures of the bucketsthat the inflow of the jet of motive fluid theretoshall be subject to aminimum of shock at the time of entry into the buckets, and that as themotive fluid passes through the buckets it shall have a graduallywidening surface for its lateral expansion up to the discharging edgesof the buckets, and that the ydirection of its discharge therefrom shallbe such that a minimum of residual energy shall be left in the escapinguid.

In carrying out my invention I s'o construct the periphery of the wheelthat its outer surface gradually diminishes in diameter from the centralcircumferential line of same to the two edges, respectively, and this Ipreferably eect by making the outer surface of the periphery of V shapein axial cross-section, with the apex of the V in the central plane andforming the greatest diameterof the wheel, or of a curve equivalentthereto. The buckets are of such shape that they mount or fitsaddle-like on the periphery. The inlet for the jet of motive iiuid isin the central part of the width of the buckets. The discharging edgesof the buckets are on each side thereof. The buckets are encircled bytwo bands or rings, (hereinafter called the encircling bands,) whichconnectv the bucketsto one another, while leaving the central part oftheir exterior face between these bands uncovered thereby. The interiorface of each bucket is at such an' angle to the inliowing jet of motivefluid that the impact of the fluid thereon is substantially free fromshock. The bucket is formed with what I term a guideduct for theinflowing fluid. This duct projects outward between the encircling bandsand is so curved forward toward the inflowing jet of motive fluid thatthe edge of the duct which first meets said jet is almost in parallelline therewith and gradually curves inward therefrom into the centralmeeting edge of cup-like concavities on each side of the bucket.Theinliowing jet of motive iiuid thus makes contact at its entry withthe inner surface of the bucket as nearly as possible free from shockand thereafter is guided in upon the meeting edges of the two sidecup-like concavities and is separated to right and left thereby andflows evenly over same to their discharging edges, which finally throwit back in nearly the opposite direction to that of the jet. Animportant feature of the buckets as compared with those hitherto inordinary use is the said guide-duct for the inflowing fluid, whereby themotive fluid on entering same makes its contact with the bucket withoutshock and is thereafter so controlled that it does not spread laterallyuntil it reaches the meeting edge of the two side cup-like concavities,whereas in Pelton wheels using similar right and left concavities whenthe uid strikes the inwardly-facing peripheral surface of the bucket ithas a tendency to spread to right and left and much of it toconsequently pass to' the lat-eral and backward returning surface of theconcavities and strike same almost at right angles, and therefore withshock, instead of gliding around same from the central meeting edges.Owing to the diiiiculty there is of showing the combination ofcurvatures by mechanical drawings, I have in the accompanyingillustrative drawings shown the buckets inperspective from a photographof an actual working wheel. Y In the drawings, Figure l is aperspectiveelevation of an impact-wheel or turbine constructed according to thisinvention, the'cover on one side of the casing inclosing same beingremoved. Fig. 2 is a perspective end view of the Wheel on a largerscale. Fig..3'is a perspective view, on a still larger scale, of theback of one bucket mounted on an axial section of the V-shaped peripheryof the wheel. Fig. 4 is a front viewlooking into bucket. Fig. 5 is aback view of bucket. Fig. 6 is a View of the outer end of bucket. Fig. 7is a side elevation of bucket. Fig. 8 is a section on line A B in Fig.4. Fig. 9 is a section on line C D in Fig. 4. Fig. IO is a view of theinner end of bucket. Fig. Il is a section on line E F in Fig. 4. Fig. 12is a section on line G H in Fig. IO.

a is the casing, in which the turbine revolves.

b is the spindle, revolving in bearing c on one side of the casing a. Onthe spindle b is mounted the wheel d, having the outer surface of itsperiphery of V shape, as shown in Fig. 3, the buckets c being mountedsaddlelikethereon. Forfurthersecuringthe bucket on the wheel when it isrevolving at very high velocities the encircling rings or bands f f aremounted and secured upon the outer shoulders o of the buckets, as shown.The buckets are also constructed to so project between the encirclingrings f f as to form the guide-ducts g, thesides n of which retain themotive iiuid from the nozzle 7L against lateral expansion until itreaches the central meeting. edges l of the cup-like concavities j j,forming the rightandleft sides of the bucket. These meeting edges thendeiiect the motive iuid without shock around said concavities to thedischarging edges m thereof, from which it is ejected in substantiallythe opposite direction to that of the iniiowing jet, with a minimum ofresidual energy left in it when the wheel is revolving at about half thevelocity of the inflowing iiuid. The discharged iiuid escapes from thecasing through the outlet k.

The exterior front wall at the top of the guide-ducts gl may be curvedslightly outward, as shown in Figs. 2 and 3, or may be parallel with theaxis of the wheel, as shown in Figs. 4, 5, and 6, and said guide-ductsmay also be projected farther forward than shown in the illustrations inadvance of the discharging edges of the right and left concavities ofthe bucket in order that the inwardlyfacing side thereof may be at asslight an angle as practicable with the line of the jet in order, ifnecessary, that the iuid may effect contact with the bucket and beguided into the cup-like concavities with a minimum of shock.

Fig. 4 shows in dotted lines how the bands fmay engage thecircumferential sides or outer shoulders o of the buckets opposite theconcavities j, and Figs. 4 to l2 show how these shoulders areapproximatelyparallel with the axis of the wheel and are also on theirouter face concentric with the circumference of the wheel. (See Fig. 8.)The discharging edges m of the concavities are approximately parallelwith the plane of the wheel-that is, approximately at right angles toits axis-and the same is approximately the case with the side walls n ofthe guide-duct at top, which walls converge as they approach the centralmeeting edge Z of the concavities. The circumferential side walls orouter shoulders o of the buckets extend in a direction approximatelyparallel with the periphery of the wheel, as best shown in Figs. 7, 8,and 9.

What I claim, and desire to secure by Letters Patent, is-

I. In impact-wheels of the Felton-wheel type, the combination with abucket-carrying wheel, of a plurality of buckets carried by said wheeland having each two cup-like concavities forming respectively the rightand left sides of the bucket, and a central guide-duct projectingoutwardly between said concavities, and encircling bands engaging thecircumferential sides of the buckets opposite said concavities, saidguide-ducts projecting between said bands, whereby motive fluid employedto drive the wheel may enter the buckets through said guide-duct betweensaid bands, and flow around said concavities interiorly to, and may bedischarged within the circumference of, said bands.

2. In impact-wheels of the Felton-wheel type, the combination with abucket-carrying wheel, of a plurality of buckets carried thereby,eachhaving two cup-like concavities forming respectively the right and leftsides of the bucket, and having the circumferential sides thereofapproximately parallel with the periphery of the carrying-wheel, and acentral guide-duct projecting outwardly between said j concavities andcommunicating with both of them for receiving the motive fiuid employedto drive the wheel and directing it into said concavities, the sides ofsaid duct being of suicient depth to control the iniiowing motive fluidagainst lateral expansion until it reaches the central meeting edges ofthe cup-like concavities, whereby the entering iuid is directed by theduct to these meeting edges and deflected by the latter into the rightand left sides of the bucket without shock.

3. In impact-wheels of the Felton-wheel type, the combination with abucket-carrying wheel, of a bucket having two cup-like concavitiesforming respectively the right and left sides of the bucket, and havingcentral meeting edges at the bottom thereof, said buckets having theircircumferential sides approximately parallel with the periphery of thesaid carrying-wheel, and having between said concavities a centralguide-duct leading to the meeting edges of said concavities, said ducthaving outwardly-projecting sides in the plane of the wheel and anapproximately-circumferential side in advance of the frontal edges ofsaid concavities.

4. In impact-wheels of the Felton-wheel type, the combination with abucket-carrying wheel havin g a periphery which in axial crosssection isof approximately V shape, in combination with buckets carried on theperiphery of said wheel, and having inner sides of approximately theshape of such periphery,

IOO

IIO

each side of said guide-duct and engaging said portions of the outersides of said concavities.

In witness whereof I have hereunto signed I5 my narne in the presence oftwo subscribing witnesses.

SAMUEL CLELAND DAVIDSON.

Witnesses:

GEORGE GooLD WARD, HUGH TAYLOR COULTER.

